Research over the last several years demonstrates that NPY signaling modulates neurobiological responses to ethanol and ethanol consumption. NPY signaling via the Y1 receptor serves as a mechanism to limit ethanol intake. Central NPY expression is driven by cAMP-dependent protein kinase (PKA) activity, and manipulations that inhibit PKA activity decrease NPY levels and increase ethanol drinking. Because of their opposing actions, it has been suggested that NPY and corticotropin releasing factor (CRF) reciprocally regulate drug self-administration through allostatic interactions within the extended amygdala. Thus, while NPY limits ethanol intake, CRF activity increases the likelihood of ethanol consumption. The allostasis model suggests that uncontrolled ethanol drinking stemming from repeated abstinence and relapse evolves as a consequence of a weakened NPY system and a hyperactive CRF system. Hence, the specific aims proposed below will test the guiding hypothesis that NPY signaling, via a reciprocal regulation of CRF, protects against increased ethanol intake. Specific experiments will address the following questions: (A) Will long-term in vivo overexpression of NPY in the extended amygdala reduce voluntary ethanol intake via Y1 receptor signaling? These studies will assess voluntary consumption of ethanol by mice following site-directed transduction with a recombinant adeno-associated virus (rAAV) vector that causes expression and constitutive secretion of NPY (rAAV-FIB-NPY). (B) Does increased voluntary ethanol intake associated with reduced NPY Y1 receptor signaling stem from unregulated CRF activity? These studies will assess ethanol consumption by Y1 receptor deficient mice following chronic administration of a CRF receptor antagonist. (C) Will long-term in vivo overexpression of NPY or chronic application of a CRF receptor antagonist limit the development of uncontrolled ethanol drinking resulting from the alcohol deprivation effect (ADE) and exposure to stressful stimuli? (D) To determine if low NPY signaling generalizes to another established model of high ethanol consumption, studies will assess whether mutant mice that lack the Rllbeta subunit of PKA have low NPY expression in the extended amygdala as predicted by recent evidence. These studies will provide important insight into the role of NPY signaling in alcohol consumption and dependence.